1. Technical Field
Illustrative embodiments generally relate to a developing device configured to develop images formed by an image forming apparatus with a developer including toner; a toner cartridge employed in the developing device; a process cartridge including the developing device; and an image forming apparatus employing the developing device, the toner cartridge, and the process cartridge.
2. Description of the Related Art
Related-art image forming apparatuses, such as a copier, a facsimile machine, a printer, or a multifunction printer having two or more of copying, printing, scanning, and facsimile functions, form a toner image on a recording medium (e.g., a sheet) according to image data using an electrophotographic method. In such a method, for example, a charger charges a surface of an image bearing member (e.g., a photoconductor); an irradiating device emits a light beam onto the charged surface of the photoconductor to form an electrostatic latent image on the photoconductor according to the image data; a developing device develops the electrostatic latent image with a developer (e.g., toner) to form a toner image on the photoconductor; a transfer device transfers the toner image formed on the photoconductor onto a sheet; and a fixing device applies heat and pressure to the sheet bearing the toner image to fix the toner image onto the sheet. The sheet bearing the fixed toner image is then discharged from the image forming apparatus.
An example of the developing device includes a one-component developing device. For example, the one-component developing device may supply toner stored in a container to a developing roller using a toner supply roller. The developing roller is pressed against a restriction blade made of metal to equalize an amount of the toner supplied to the developing roller. The toner on the developing roller is then supplied to a photoconductor to develop the electrostatic latent image formed on the photoconductor.
The toner deteriorates as it passes repeatedly between the toner supply roller and the developing roller, and the developing roller and the restriction blade in the one-component developing device. Further, when the toner not used for development is returned to the container from the developing roller, heavy friction occurs between the toner and an agitator provided in the container to agitate the toner. As a result, deterioration of the toner is accelerated, thereby degrading chargeability of the toner.
The agitator may, for example, have a paddle-like shape. An agitator 140 having a paddle-like shape illustrated in FIG. 1 can agitate and convey the toner with greater force. However, the greater force causes greater stress on the toner, thereby degrading the toner.
To reduce stress on the toner, the agitator may have a wire or plate member. Because such an agitator does not have a larger area in a direction of rotation thereof, collision between the agitator and the toner can be reduced. For example, Published unexamined Japanese Patent Application No. H05-11605 discloses a developing device including an agitator 25 having a U-shaped wire member in a toner container 24 as illustrated in FIG. 2. The agitator 25 is rotated in an area lower than a protrusion 7 to agitate the toner in the toner container 24 to supply the toner to a developing roller 26. Because the agitator 25 including the U-shaped wire member does not cause larger stress to the toner, the problem of deterioration in the toner can be solved. However, another problem may arise in that the toner cannot be sufficiently agitated and smoothly conveyed by the agitator 25.